Per the article linked below re a new synthetic diamond that’s 50% harder than natural diamonds. How can the synthetic be 50% harder if the material’s crystal structure is essentially the same?
Large Diamonds Made From Gas Are Hardest Yet
One reason is because there are atomic level flaws in all natural crystal structures. These could be missing atoms or atoms in the wrong locations. Crystal synthesis techniques allow you to minimize the number of flaws in a given structure and thus change the material properties of the final product i.e. making it harder.
Well, natural diamonds are typically not as perfect as synthetic diamonds. I don’t know about 50% harder, but it wouldn’t surprise me to find that the more perfect a diamond’s crystal structure is the harder it is. I know that jewelers typically can tell natural from synthetic diamonds under a microscope because the synthetics have fewer flaws.